Estimates of tissue perfusion parameters are important for diagnosis, treatment planning and treatment of a variety of diseases e.g. ischemic conditions and tumors involving the brain, heart, liver as well as other organs. Perfusion measurements performed with conventional digital subtraction angiography (DSA) are very limited since the two-dimensional nature of these examinations superimposes the tissue perfusion bed from multiple overlapping planes. For example, attempts to measure coronary artery flow reserve using a 2D technique may be limited by the overlapping of vascular beds in the available projection images.
With time resolved 3D information (referred to herein as “4D”), the perfusion signals from the tissue can be separately displayed for any plane without overlap. U.S. patent application Ser. No. 12/692,340, filed Jan. 22, 2010 and entitled SYSTEM AND METHOD FOR FOUR DIMENSIONAL ANGIOGRAPHY AND FLUOROSCOPY describes 4D DSA techniques for displaying time resolved 3D image volumes. The entire contents of the foregoing application are incorporated by reference herein. This method is based on angiographic acquisitions obtained using a C-arm flat detector angiographic apparatus. In this implementation a limited number (e.g., two or less) projections are used in conjunction with a 3D rotational DSA reconstruction to generate a time resolved sequence of 3D vascular volumes. However, signals in the perfusion bed were not adequately reconstructed. As used herein, the term 4D DSA vascular reconstruction refers to a measurement of this type.
Accordingly, it would be advantageous to provide an imaging method which provides time resolved 3D volume reconstructions which preserve information about the perfusion bed.